Damage and fracture analyses of wire with off-center inclusion on multi-pass drawing under different back tensions

The occurrence of fracture during wire drawing seriously reduced the quality of steel wire. In this study, the morphology of necking fracture and microstructure of wire are observed by SEM. It is found that there is large off-center inclusion on the surface of some fractures. Meanwhile, void defects appear near the inclusions, especially along the drawing direction. The FEM is employed to simulate multi-pass drawing of wire with and without off-center inclusion under different back tensions. The results show that with the increase of back tension, the damage in the core of wire without inclusion gradually accumulates. When the damage exceeds the critical value, cracks occur preferentially in the wire core and propagate to the surface of wire, thus forming as necking fracture. When the wire contains inclusion, cracks will first occur at both ends of inclusion, and its fracture is formed earlier than the wire without inclusion.